One of the methods currently used for operations of refueling or transferring comprises a telescoping tube, which in turn comprises a fixed part and a mobile part, having said mobile part the capacity to be extended telescopically with respect to the fixed part, carrying out in this manner the transfer of fuel from one tank to another.
For the specific case of air to air fuel transfer between a tanker aircraft and a receiver aircraft, this telescoping tube is normally directed by an operator or boomer stationed in the tanker aircraft and who operates said telescoping tube until the end of the same, called the nozzle, makes contact with a receptacle in the receiver aircraft. The end of the tube or nozzle comprises some latches. On the other side, the receptacle of the receiver aircraft comprises some triggers, normally activated by hydraulic means, said triggers having the purposes of attaching and blocking the nozzle of the telescoping tube by means of the clamps on said tube. Once the nozzle makes contact and connects to the receptacle, the boomer may commence the transfer of fuel from the tanker aircraft to the receiver aircraft in a safe manner.
Once refueling has finished, it is necessary to disconnect the telescoping tube from the receiving aircraft. Said disconnection is generally carried out in such a way that the boomer in the tanker aircraft issues an order for normal disconnection that consists in a request, by means of an electrical signal, to the triggers in the receptacle to free the latches of the telescoping tube that are retaining the end of the same in the receptacle of the receiving aircraft. Thus the triggers are retracted, freeing the latches on the nozzle of the telescoping tube. Once the nozzle has been completely freed, the boomer may then begin retracting the telescoping tube. In other cases, it is the receptacle in the receiving aircraft that initiates disconnection of the telescoping tube of the receiving aircraft, directly retracting the triggers of the receptacle and generating an electrical signal that informs the boomer in the tanker aircraft of the disconnection. Finally, the boomer in the tanker aircraft can also free the latches on the nozzle of the telescoping tube, including with the triggers of the receptacle closed by means of an integrated independent disconnection in the nozzle. In this final case, an electrical pulse is also generated to report the disconnection to the receptacle.
The systems known in the state of the art control the connection and disconnection of the nozzle of the telescoping tube from the receptacle on the receiving aircraft by means of some systems of induction coils, a primary system of induction coils located in the nozzle and a system of secondary induction coils deployed in the receptacle in such a way that the connection or disconnection of the nozzle from the receptacle is controlled by the characteristics of the current induced in the primary and secondary induction coil systems which are facing each other.
In this way, when the connection is made between the nozzle of the tanker aircraft with the receptacle in the receiving aircraft, the secondary induction coil system induces a current in the primary induction coil system in the nozzle, and by means of visual observation on the part of the boomer, he is able to detect that the nozzle is connected to the receptacle, subsequently commencing the refueling sequence manually. All of this implies controlling a process that is extremely delicate in a manual way and by means of induced magnitudes, which is not, therefore, as trustworthy a process as would be desired.
On the other hand, when the disconnection of the nozzle from the receptacle is ordered, the receiving aircraft indicates the activation of the disconnecting mechanism, sending an electrical signal that causes an electrical current in the secondary coil system to be created, which induces an electrical current in the primary coil system of the nozzle, indicating to the boomer that the disconnection of the nozzle from the receptacle is going to proceed. This means that latches of the nozzle begin to be freed, at the same time that the receptacle orders its triggers to begin withdrawing. Again in this case, the boomer in the tanker aircraft detects the disconnection process by means of induced measurements, and so the process is not as trustworthy as is should be for actions of this kind.
In the case in which the boomer is the one who initiates the disconnection by the normal system or by the independent disconnection system, the tanker aircraft generates a current on the primary induction coil system that induces a voltage in the secondary induction system of the receptacle. In this way the receiving aircraft detects through induced means the intention of the boomer of the tanker aircraft to disconnect the nozzle, or free the latches of the nozzle. This system is not completely reliable as would be desired for actions of this type, as they are carried out through induced means.
Furthermore, none of the documents of the known state of the art are able to provide information regarding the status of the connection of the nozzle of the telescoping tube with respect to the receptacle of the receiving aircraft. These known systems simply provide a physical means of communication between the induction coils of the receiving and tanker aircraft, in such a way that the status of the connection of the nozzle is simply “induced” from the count of the number of transitions transmitted by means of the nozzle. This is neither reliable nor capable of providing all of the information of the status of the connection that is needed to carry out a safe refueling process.
Consequently it would be desirable to have system available that would be able to detect the connection and disconnection of the nozzle of the telescoping tube of a tanker aircraft in the receptacle of the receiving aircraft during air to air fuel transfer operations in a reliable manner, such that it would also provide information with regard to the status of the connection of said nozzle in the receptacle to which fuel is being transferred. In this way this system should provide information on whether the nozzle is inserted in the receptacle, as well as information on the status of the latches of the nozzle and the triggers of the receptacle.
Hence the present invention is directed towards providing these functions.